The subject invention is directed to the art of driving rods into the ground and extracting rods from the ground. More particularly, the invention concerns a rod driving tool having three or more driving, or rod end impacting, means; two carried within the handle of the tool and at least one more driving means on the head of the tool. Additionally, the invention concerns an extractor tool carried by the handle of the rod driving tool.
Long rods are driven into the ground for a variety of reasons. Concrete reinforcing bar, or rebar, is often driven into the ground at the beginning of construction projects, such as in building, bridge, or silo construction. Utility company personnel drive ground rods into the earth for fault control and to prevent unwanted voltage fluctuations to power distribution systems. Electrical contractors also drive highly conductive electrical grounding rods into the ground to provide proper grounding for all electrical services. Metal building contractors drive ground rods every 100 lineal feet to provide building bonding and grounding as per the National Electrical Code. Fence builders drive rods into the ground and, in the case of electrical fences, also drive ground rods into the ground. Lightning contractors use electrical grounding rods as a means of protection from lightning strike damage. Computer, data and security systems require proper grounding if not already provided by the main electrical service.
These rods are often made of a steel and may be coated with a more highly conductive coating. They may have a pointed end to assist with ground insertion and driving, and a flat end for being struck. They are typically driven by a person swinging a sledge hammer while another person holds the rod in the desired location and to keep it steady. As these rods are often eight feet long, or longer, one or both of the people may be on ladders, or atop some other object, to be elevated to a position where the rod can effectively be struck and driven. At a new building construction site, where such installations often take place, the ground may be uneven or soft, thereby making ladder placement and use both difficult and dangerous for either or both persons. In addition, by requiring two people to drive a given rod into the ground and having one or both of them need ladders to be able to strike the rod end with the sledge hammer adds significant time and expense to any given rod installation.
In addition to being more timely and costly, rod installation in this manner with two people can be dangerous. The person swinging the sledge hammer sometimes misses the mark, either completely, or partially, thereby resulting in a glancing blow with a dangerous deflecting sledge hammer head. The person holding the rod can be injured by a direct impact on the hands or arms with a missed swing of the hammer, or they can be struck elsewhere on their person by the deflected hammer head. Also, since grounding rods are typically driven into the earth close to buildings, the building could be damaged by the glancing sledge hammer head breaking windows or causing other damage.
Another serious problem that often occurs with driving a rod into the ground by repeatedly impacting an end of the rod with a sledge hammer is that the rod may become damaged. The rod end may become deformed or the rod may be bent due to an off center and non-square impact with a hammer face of the sledge. When driving electrical grounding rods, for example, deformed, or even mushroomed, rod ends do not allow electrical grounding connectors to be slipped over the rod end. These rods have to have their ends re-worked. Typically, this may be done by filing down the deformed end in place so that the connector will slide on. In severe cases, the rod must be dug out and scrapped, a further time-consuming and costly measure. Bent rods are similarly scrapped.
A number of rod driving devices are known that overcome some of the problems with driving rods using sledge hammers. Among these, U.S. Pat. No. 5,086,849 to Dahl discloses a rod driving tool formed of three tightly bundled tubular members having a common upper elevation. Use of the device to drive a rod into the ground is done in steps. The device requires use of a separate extension piece to fully drive a rod into the ground. Although this tool is disclosed to permit rod installation by one laborer, it is disclosed to be lengthy and requiring a separate piece, an extension element, to drive the rod all the way to the surface level.
U.S. Pat. Nos. 5,248,002 and 5,337,836 to Williams disclose a tool and method, respectively, to drive a rod into the ground. The device has a handle with a bore opening for receiving a rod, a hammer head connected to the handle at the opposite handle end to the bore opening and a removable weight connected with the hammer head. The removable weight is connected to the hammer head via a bolt that passes through the weight and into the hammer and at least one pin inserted in corresponding apertures in the weight and in the hammer head. The weight has an aperture in an end face of it for placement over a partially installed rod. The opposite end face of the weight then acts as a striking surface for the hammer, thereby allowing a partially installed rod to be further driven into the earth. Again, this tool is disclosed to permit rod installation by one laborer, however, it too has multiple pieces that can be easily lost. In addition to requiring multiple pieces, the disclosed tool requires the user to start a rod by holding the handle and balancing the weighty hammer head with additional weight attached in the cumbersome starting position, well over their head. This can be awkward and make angled rod insertions difficult.
Another rod driving tool said to permit a single laborer to install a rod while standing on the ground is disclosed in U.S. Pat. No. 4,557,409 to Hecock et al. This device is cylindrical and has hammers secured at each end. Either hammer can be brought to selectively impact with a single anvil connected to a drive shaft that has a recess to slide over a rod end to be driven. The outer cylinder with hammers and the drive shaft with anvil are two separate pieces. The device works as a slide hammer with the outer cylinder lifted with respect to the drive shaft and brought down to impact either hammer, as selected, with the anvil to drive the rod. The device has locking means in the form of a pin and corresponding openings to secure the two pieces together in a storage position.
The invention allows a single user to drive a long rod, such as an eight foot electrical grounding rod, into the ground while standing firmly on the ground with a single, affordable manual tool. The tool requires no separate pieces that can be lost, nor does it have any moving parts that can wear, become dirty and jam. The tool of the present invention contains at least three rod-driving means, typically used for starting, intermediate and final installation of a rod, respectively. The tool includes a handle connected to a head. The handle includes two of the rod-driving means contained within it. The handle has rod-receiving bore openings at each of the two handle ends, each of which communicates through a corresponding hollow handle section to a respective striking surface disposed within the handle somewhere between the two handle ends. The head contains the third driving means in the form of a striking face, such as a hammer face. Of course, as is the case with a sledge hammer head, the head may have more than one striking face and still be within the present invention. Additionally, rod extractor means in the form of a hole cross-wise through the handle and sized to slip over a rod end and at least a section of the rod to be extracted, and used to pry the rod up from the ground, are carried by the rod driving tool in an embodiment of the present invention. The invention also concerns methods of using such an inventive tool to drive a rod into the ground and, in an embodiment of the tool, to extract a rod from the ground.
In one embodiment, the first hollow handle section is longer than the second hollow handle section and includes the handle end connected with the head. The worker slides the rod end to be impacted through the rod receiving opening of the first hollow handle section and the head. The head may resemble a sledge hammer head having two striking faces, for example, and may be similarly weighted. The worker then places the other rod end at the desired installation location and angle in contact with the ground. The rod does not have to be driven vertically, but can be installed at an angle, as desired, with the inventive tool. The worker may grasp the head or the handle of the tool and lift the tool with respect to the rod so that a portion of the first hollow handle section still surrounds the rod. Lifting the tool with respect to the rod in this inventive embodiment is relatively easy and controllable, since the head forms the majority of the tool overall weight and is near the worker""s own head when impacting the rod end while vertically inserting an eight foot standard length grounding rod, for example. To drive the rod the worker then forcefully brings the tool down so that the striking surface at the end of the first hollow section within the handle impacts the rod end, thereby driving the rod into the ground. This process is repeated until the rod is partially installed as desired. The rod can be inserted using the first drive means such that the exposed portion of the rod above ground surface level is limited by the length of the first hollow handle section.
At this point, the worker removes the tool from surrounding engagement with the rod and slides the second rod receiving opening at the opposite handle end over the rod so that a portion of the rod is surrounded by the second hollow handle section. The worker can then hold the handle or the head of the tool, now with the head at a vertically higher elevation of the tool such that it is above the rod end within the tool handle, and similarly drive the rod with the corresponding striking surface at the end of the second hollow handle section impacting the rod end. In this manner, the heavy head of the tool is at a manageable elevation, typically near or below a standing worker""s head level. The worker can drive the rod in this manner up to or beyond the limit of the second hollow handle section hitting the ground. The second hollow handle section can be driven, with the rod into the ground to fully drive the rod, in some installations.
If needed, final installation of the rod may be made with the tool used as a conventional hammer, with the worker holding the handle and swinging the head down to impact the rod end with the striking face of the head, thereby driving the rod down into the ground as desired.
A tool user can selectively use any of the at least three driving means as desired, the choice typically depending on whether the user is starting to drive a rod into the ground, driving a partially installed rod into the ground, or finishing the driving of the rod into the ground. In the event a partially installed rod needs to be removed, such as when it is discovered the rod is not in the correct location or when a subsurface blockage is encountered preventing further installation, an embodiment of the tool provides integral rod extractor means. The rod extractor takes the form of a hole cross-wise through the handle. In one embodiment, the extractor hole is through a solid section of material within the handle that serves to also form the first and second striking surfaces on its ends within the first and second hollow sections of the handle. A user turns the tool horizontal and slides the extractor hole of the tool over the exposed rod end of the partially installed rod until the tool is in contact with the ground at both the head and opposite handle end. The user then lifts one end of the tool with the other end contacting the ground as a pry surface. The extractor hole grips and lifts the rod. This process may have to be repeated, as desired, to extract the rod as needed. In the embodiment of the tool with the longer first hollow handle section having an end connected with the head and an extractor tool interconnected between its other end and a shorter second hollow handle section, extracting a rod would preferably be done by lifting the head end of the tool, thereby benefiting from the larger moment arm.